Hey
Trinitrotoluene, nice to see you again bro. From my previous experience in using Rain teams, I believe that
Rotom-W will help you better than Starmie. The main reason is because, without Dragonite, you don´t have an SR weak pokemon to abuse and therefore Starmie´s job is relegated. I would also like to add that with Jirachi´s Wish support, hazards shouldn´t be so troublesome. I would also like to back up
DestinyUnknown´s suggestion of using
Encore on Politoed, a smart Gyarados user can still scout Rotom-W under a Sub by hiding again under this same move and set-up, gaining boosts. The real prize of Encore comes that you won´t be taking out serious damage unlike Perish Song. Just wanted to back up this two excellent suggestions as other people did already a great job rating this team! Hope it helps :)